package cn.zyjblogs.nio.groupchat;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.StandardCharsets;
import java.util.Iterator;
import java.util.Scanner;

public class GroupChatClient {
    //定义相关属性
    private final String HOST = "127.0.0.1";
    private static final int PORT = 6667;
    //定义属性
    private Selector selector;

    private SocketChannel socketChannel;
    private String username;
    //构造器
    public GroupChatClient(){
        try {
            selector = Selector.open();
            //连接服务器
            socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT));
            socketChannel.configureBlocking(false);
            socketChannel.register(selector, SelectionKey.OP_READ);
            //获得username
            username = socketChannel.getLocalAddress().toString().substring(1);
            System.out.println(username + " is ok .....");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //向服务器发送消息
    public void sendInfo(String info){
        info = username +" 说: "+info;
        try {
            socketChannel.write(ByteBuffer.wrap(info.getBytes(StandardCharsets.UTF_8)));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //读取服务端回复的消息
    public void readInfo(){
        try {
            int readChannels = selector.select();
            if (readChannels > 0){
                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                while (iterator.hasNext()){
                    SelectionKey selectionKey = iterator.next();
                    if (selectionKey.isReadable()){
                        SocketChannel channel = (SocketChannel)selectionKey.channel();
                        //得到一个Buffer
                        ByteBuffer buffer = ByteBuffer.allocate(1024);
                        //读取数据到缓冲区
                        channel.read(buffer);
                        String msg = new String(buffer.array());
                        System.out.println(msg.trim());
                    }
                }
                //删除当前的selectionKey 防止重复操作
                iterator.remove();
            }else {
                //System.out.println("没有可用的通道....");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        //启动客户端
        GroupChatClient chatClient = new GroupChatClient();
        //启动一个线程 每3秒 读取从服务器发送的数据
        new Thread(()->{
            while (true){
                chatClient.readInfo();
                try {
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();
        //发送数据给服务器端
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()){
            String s = scanner.nextLine();
            chatClient.sendInfo(s);
        }
    }
}
